<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>

  <body>
    <div id="app"></div>
    <template id="pengfan">
      <button @click="changeFirstName">修改firstName</button>
      <h2>{{fullName}}</h2>
      <h2>{{fullName}}</h2>
      <h2>{{fullName}}</h2>
      <h2>{{fullName}}</h2>
      <h2>{{fullName}}</h2>

      <h2>{{getFullName()}}</h2>
      <h2>{{getFullName()}}</h2>
      <h2>{{getFullName()}}</h2>
      <h2>{{getFullName()}}</h2>
      <h2>{{getFullName()}}</h2>
      <h2>{{getFullName()}}</h2>
    </template>
    <script src="../js/vue.js"></script>
    <script>
      Vue.createApp({
        template: "#pengfan",
        data() {
          return {
            message: "Hello World",
            firstName: "Kobe",
            lastName: "Bryant",
          };
        },
        computed: {
            //计算属性是有缓存的，当我们多次使用计算属性时，计算属性中的运算只会执行一次
            // 计算属性会随着依赖的数据（firstName）的改变，而进行重新计算
          fullName() {
            console.log("computed的fullName中的计算");
            return this.firstName + " " + this.lastName;
          },
        },
        methods: {
          getFullName() {
            console.log("methods的getFullName中的计算");
            return this.firstName + " " + this.lastName;
          },
          changeFirstName() {
              this.firstName = "pengfan"
          }
        },
      }).mount("#app");
    </script>
  </body>
</html>
